The disclosed embodiments of the present invention relate to processing an input signal to generate a transport stream having packets included therein, and more particularly, to signal processing apparatuses capable of reducing complexity of back-end processing and/or reducing memory requirement by applying packet identifier (PID) filtering to transport stream packets initially reproduced from an input signal prior to buffering the transport stream packets.
In contrast to the analog television system using analog signals to carry audio and video information, a digital television (DTV) system sends and receives audio and video information by means of digital signals. For example, at the transmitter end, the audio and video information to be transmitted is first packetized into transport stream (TS) packets, and then the TS packets are modulated and transmitted by broadcasting techniques. Regarding the receiver end, a demodulator is required for demodulating a modulated input signal received via a tuner and an antenna to reproduce TS packets from the modulated input signal, and a smoothing buffer is generally implemented for buffering the demodulator output to smooth the TS packet output fed into the following back-end processing block. In other words, the demodulator in the conventional receiver design stores all of the reproduced TS packets into the smoothing buffer before the TS packets are processed by the back-end processing block. In the back-end processing block, a packet identifier (PID) filter is implemented for processing and de-multiplexing TS packets according to PIDs of the TS packets, which may require additional buffers for temporary data storage.
In view of above, the number of buffers and the buffering size of the conventional receiver design are large, leading to larger circuit area, higher production cost, and higher back-end processing complexity.